The azide ion, n−3, is a symmetrical ion, all of whose contributing structures have formal charges. draw three important contributing structures for this ion. draw the molecule by placing atoms on the grid and connecting them with bonds. include all nonbonding electrons. show the formal charges of all atoms.

Explanation:

Contributing structures are the resonating structures which are formed due to the delocalization of electrons in a molecule.

The azide ion that is , is a symmetrical ion, all of whose contributing structures have formal charges.

Lone pair of central nitrogen atom in azide ion is in conjugation with the neighboring nitrogen atoms.

Contributing structures of azide ion are drawn in the image attached.

the correct answer is:

a. formation of precipitation